U.S. patent application number 13/497831 was filed with the patent office on 2013-04-25 for base of surface-mount electronic component package, and surface-mount electronic component package.
This patent application is currently assigned to DAISHINKU CORPORATION. The applicant listed for this patent is Minoru Iizuka, Yuka Kojo. Invention is credited to Minoru Iizuka, Yuka Kojo.
Application Number | 20130098654 13/497831 |
Document ID | / |
Family ID | 44762473 |
Filed Date | 2013-04-25 |
United States Patent
Application |
20130098654 |
Kind Code |
A1 |
Iizuka; Minoru ; et
al. |
April 25, 2013 |
BASE OF SURFACE-MOUNT ELECTRONIC COMPONENT PACKAGE, AND
SURFACE-MOUNT ELECTRONIC COMPONENT PACKAGE
Abstract
A base of a surface-mount electronic component package holds an
electronic component element and is to be mounted on a circuit
board with a conductive bonding material. The base has a principal
surface and an external connection terminal to be electrically
connected to the circuit board. The external connection terminal is
formed in the principal surface. The base includes a bump formed on
the external connection terminal. The bump is smaller than the
external connection terminal. The base has a distance d between an
outer periphery end edge of the external connection terminal and an
outer periphery end edge of the bump along an attenuating direction
of stress on the external connection terminal The stress is
generated in association of mounting of the base on the circuit
board. The distance d is more than 0.00 mm and equal to or less
than 0.45 mm.
Inventors: |
Iizuka; Minoru;
(Kakogawa-shi, JP) ; Kojo; Yuka; (Kakogawa-shi,
JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Iizuka; Minoru
Kojo; Yuka |
Kakogawa-shi
Kakogawa-shi |
|
JP
JP |
|
|
Assignee: |
DAISHINKU CORPORATION
Kakogawa-shi,
JP
|
Family ID: |
44762473 |
Appl. No.: |
13/497831 |
Filed: |
March 24, 2011 |
PCT Filed: |
March 24, 2011 |
PCT NO: |
PCT/JP11/57204 |
371 Date: |
March 23, 2012 |
Current U.S.
Class: |
174/50.5 ;
174/50 |
Current CPC
Class: |
H01L 2924/15162
20130101; H01L 2924/16195 20130101; H03H 9/1021 20130101; H01L
2924/0002 20130101; H05K 5/0095 20130101; Y02P 70/50 20151101; H01L
23/053 20130101; H01L 23/49805 20130101; Y02P 70/613 20151101; H01L
23/49838 20130101; H05K 2201/09381 20130101; H05K 3/3431 20130101;
H05K 2201/10075 20130101; H05K 3/3442 20130101; H05K 2201/10068
20130101; H01L 23/13 20130101; H05K 5/0091 20130101; H01L 2924/0002
20130101; H01L 2924/00 20130101 |
Class at
Publication: |
174/50.5 ;
174/50 |
International
Class: |
H05K 5/00 20060101
H05K005/00 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 1, 2010 |
JP |
2010-085232 |
Claims
1. A base of a surface-mount electronic component package to hold
an electronic component element and to be mounted on a circuit
board with a conductive bonding material, the base comprising: a
principal surface; at least one external connection terminal to be
electrically connected to the circuit board, the at least one
external connection terminal being formed in the principal surface;
a bump formed on the at least one external connection terminal, the
bump being smaller than the at least one external connection
terminal; and a distance d between an outer periphery end edge of
the at least one external connection terminal and an outer
periphery end edge of the bump along an attenuating direction of
stress on the at least one external connection terminal, the stress
being generated in association of mounting of the base on the
circuit board, the stress attenuating along the attenuating
direction of stress, wherein the distance d is more than 0.00 mm
and equal to or less than 0.45 mm.
2. The base of a surface-mount electronic component package
according to claim 1, wherein the distance d is more than 0.00 mm
and equal to or less than 0.12 mm.
3. The base of a surface-mount electronic component package
according to claim 1, wherein the distance d is equal to or more
than 0.06 mm and equal to or less than 0.45 mm.
4. The base of a surface-mount electronic component package
according to claim 1, wherein the distance d is equal to or more
than 0.06 mm and equal to or less than 0.12 mm.
5. The base of a surface-mount electronic component package
according to claim 1, wherein an imaginary line passes on the outer
periphery end edge of the at least one external connection terminal
and the outer periphery end edge of the bump, and wherein an angle
of the imaginary line relative to a surface of the at least one
external connection terminal is in a range of 8.degree. to
18.degree..
6. The base of a surface-mount electronic component package
according to claim 1, wherein the at least one external connection
terminal comprises four external connection terminals respectively
formed at four corners of the principal surface, and wherein the
attenuating direction of stress on each of the four external
connection terminals is oriented from each of the four corners of
the principal surface toward a center point of the principal
surface.
7. The base of a surface-mount electronic component package
according to claim 1, wherein the at least one external connection
terminal comprises a pair of opposing external connection terminals
formed along a pair of respective sides of the principal surface,
and wherein the attenuating direction of stress on each of the pair
of external connection terminals is oriented from a corner portion
of each of the external connection terminals closest to a corner of
the principal surface toward a side of each of the external
connection terminals closest to a center point of the principal
surface.
8. The base of a surface-mount electronic component package
according to claim 1, wherein the at least one external connection
terminal comprises a pair of external connection terminals formed
at respective diagonal positions of the principal surface, and
wherein the attenuating direction of stress on each of the pair of
external connection terminals is oriented from a corner portion of
each of the external connection terminals disposed at a corner of
the principal surface toward a diagonal portion of each of the
external connection terminals disposed at a diagonal position
relative to the corner portion.
9. The base of a surface-mount electronic component package
according to claim 1, wherein the bump has a thickness increasing
along the attenuating direction of stress.
10. The base of a surface-mount electronic component package
according to claim 1, wherein the base and the circuit board have
different coefficients of thermal expansion.
11. A surface-mount electronic component package to be mounted on a
circuit board, the surface-mount electronic component package
comprising: the base of a surface-mount electronic component
package according to claim 1 to hermetically seal an electronic
component element; and a lid.
Description
TECHNICAL FIELD
[0001] The present invention relates to a base of a surface-mount
electronic component package, and a surface-mount electronic
component package.
BACKGROUND ART
[0002] Surface-mount electronic component packages (hereinafter
referred to as "packages") are applicable to electronics devices
and the like, specifically to surface-mount piezoelectric resonator
devices (hereinafter referred to as "piezoelectric resonator
devices") such as crystal resonators, crystal filters, and crystal
oscillators.
[0003] A piezoelectric resonator device includes a crystal
resonator plate with metal film electrodes on both principal
surfaces of the crystal resonator plate. The crystal resonator
plate is disposed in a package. The package hermetically seals the
metal film electrodes to protect the metal film electrodes from
ambient air. Piezoelectric resonator devices of this kind generally
have packages made of ceramic material in view of demands
associated with surface mounting of parts (see, for example, Patent
Citation PLT 1).
[0004] PLT 1 discloses a surface-mount resonator as a piezoelectric
resonator device. The surface-mount resonator includes a base
(referred to as "a mounting board" in PLT 1) made of ceramic
material and a lid (referred to as "a cover" in PLT 1). The casing
of the surface-mount resonator is composed of a rectangular
parallelepiped shaped package. In the internal space of the
package, a piezoelectric resonator piece (referred to as "a quartz
crystal piece" in PLT 1) is held and bonded on the base. The
package with the piezoelectric resonator piece held and bonded
therein is bonded on a circuit board made of glass epoxy material
with a solder, thus electrically connecting the circuit board to an
external connection terminal formed on the base.
CITATION LIST
Patent Literature
[0005] PLT 1: Japanese Unexamined Patent Application Publication
No. 2002-76813.
SUMMARY OF INVENTION
Technical Problem
[0006] With the technique described in PLT 1, the base is bonded on
the circuit board with a solder. Unfortunately, the circuit board
(a glass epoxy material) and the base (a ceramic material) have a
difference in coefficients of thermal expansion. This causes heat
fatigue and/or a creep that in turn cause a solder crack during the
mounting of the base on the circuit board. The solder crack causes
a problem of electrical disconnection between the base and the
circuit board. The solder crack, as used herein, occurs along the
external connection terminal formed on the base.
[0007] The present invention has been made to solve the
above-described problems, and it is an object of the present
invention to provide a package and a base of the package that
improve the durability of the solder and minimize the electrical
disconnection of the package from the circuit board.
Solution to Problem
[0008] In order to achieve the above-described object, according to
one aspect of the present invention, a base holds an electronic
component element and is to be mounted on a circuit board with a
conductive bonding material. The base has a principal surface and
at least one external connection terminal to be electrically
connected to the circuit board. The at least one external
connection terminal is formed in the principal surface. The base
includes a bump formed on the at least one external connection
terminal The bump is smaller than the at least one external
connection terminal. The base has a distance d between an outer
periphery end edge of the at least one external connection terminal
and an outer periphery end edge of the bump along an attenuating
direction of stress on the at least one external connection
terminal The stress is generated in association of mounting of the
base on the circuit board. The stress attenuates along the
attenuating direction of stress. The distance d is more than 0.00
mm and equal to or less than 0.45 mm.
[0009] With this aspect of the present invention, the external
connection terminal to be electrically connected to the circuit
board with the conductive bonding material is formed in the
principal surface. The bump that is smaller than the external
connection terminal is formed on the external connection terminal.
The distance d along the attenuating direction of stress is more
than 0.00 mm and equal to or less than 0.45 mm. This improves the
durability of the conductive bonding material and minimizes the
electrical disconnection of the package from the circuit board.
[0010] Specifically, with this aspect of the present invention,
forming the bump on the external connection terminal ensures that
even if a crack occurs on the conductive bonding material, the
crack on the conductive bonding material does not develop along the
external connection terminal of the base, but instead develops from
an outer periphery end edge of the external connection terminal
toward an outer periphery end edge of the bump. Thus, a bending
point is ensured where the crack is bent in its course. The bending
point impedes the advancement of a crack itself. This aspect of the
present invention also ensures that even if a crack occurs on the
conductive bonding material, the electrical disconnection of the
base from the circuit board is more securely minimized as compared
with the conventional art without the bump. This, as a result,
improves the durability of the conductive bonding material. This
configuration ensures that the distance of positive-negative
reversal of the direction of strain is extended to equal to or more
than 1.5 times as compared with the conventional art without the
bump. This, as a result, reduces the rate of crack advancement on
the conductive bonding material.
[0011] In the above configuration, the distance d may be more than
0.00 mm and equal to or less than 0.12 mm.
[0012] This configuration, in which the distance d is more than
0.00 mm and equal to or less than 0.12 mm, eliminates the
positive-negative reversal of strain. This minimizes the
advancement of a crack on the conductive bonding material, which
would otherwise advance due to the positive-negative reversal of
strain. It is particularly preferred that the distance d is 0.12
mm, in which case the positive-negative reversal of strain is
eliminated, and a long distance d is ensured.
[0013] In the above configuration, the distance d may be equal to
or more than 0.06 mm and equal to or less than 0.45 mm.
[0014] This configuration keeps the Maximum von Mises Stress at
equal to or less than 5.00 E+11 Pa, and the reduction in Maximum
von Mises Stress minimizes the amount of cracks. In particular, the
Maximum von Mises Stress is minimized at a distance d of 0.12
mm.
[0015] In the above configuration, the distance d may be equal to
or more than 0.06 mm and equal to or less than 0.12 mm.
[0016] This configuration, in which the distance d is equal to or
more than 0.06 mm and equal to or less than 0.12 mm, eliminates the
positive-negative reversal of strain. This minimizes the
advancement of a crack on the conductive bonding material, which
would otherwise advance due to the positive-negative reversal of
strain. Additionally, the Maximum von Mises Stress is kept at equal
to or less than 5.00 E+11 Pa, and the reduction in Maximum von
Mises Stress minimizes the amount of cracks. In particular, strain
and the Maximum von Mises Stress are minimized at a distance d of
0.12 mm.
[0017] In the above configuration, an imaginary line may pass on
the outer periphery end edge of the at least one external
connection terminal and the outer periphery end edge of the bump,
and an angle of the imaginary line relative to a surface of the at
least one external connection terminal may be in a range of
8.degree. to 18.degree..
[0018] This configuration, in which the angle of the imaginary line
relative to a surface of the external connection terminal is in a
range of 8.degree. to 18.degree., eliminates the positive-negative
reversal of strain. This minimizes the advancement of a crack on
the conductive bonding material, which would otherwise advance due
to the positive-negative reversal of strain.
[0019] In the above configuration, the at least one external
connection terminal may include four external connection terminals
respectively formed at four corners of the principal surface. The
attenuating direction of stress on each of the four external
connection terminals may be oriented from each of the four corners
of the principal surface toward a center point of the principal
surface. The present invention is applicable to a four-terminal
configuration that includes the four external connection terminals
formed at the respective four corners of the principal surface.
[0020] In the above configuration, the at least one external
connection terminal may include a pair of opposing external
connection terminals formed along a pair of respective sides of the
principal surface. The attenuating direction of stress on each of
the pair of external connection terminals may be oriented from a
corner portion of each of the external connection terminals closest
to a corner of the principal surface toward a side of each of the
external connection terminals closest to a center point of the
principal surface. The present invention is applicable to a
two-terminal configuration that includes the pair of opposing
external connection terminals formed along a pair of respective
sides of the principal surface.
[0021] In the above configuration, the at least one external
connection terminal may include a pair of external connection
terminals formed at respective diagonal positions of the principal
surface. The attenuating direction of stress on each of the pair of
external connection terminals may be oriented from a corner portion
of each of the external connection terminals disposed at a corner
of the principal surface toward a diagonal portion of each of the
external connection terminals disposed at a diagonal position
relative to the corner portion.
[0022] This configuration, in which a pair of external connection
terminals are disposed diagonally on the principal surface of the
base, ensures that even if a difference in coefficients of thermal
expansion exists between the base and the circuit board, the base
rotates about the center point of the principal surface to
uniformly distribute the stress.
[0023] In the above configuration, the bump may have a thickness
increasing along the attenuating direction of stress.
[0024] This configuration, in which the thickness of the bump
increases along a direction in which the stress attenuates, causes
a crack to develop along a surface of the bump. This ensures that
even if a crack occurs on the conductive bonding material, the
electrical disconnection of the base from the circuit board is more
securely minimized as compared with the conventional art without
the bump. This, as a result, improves the durability of the
conductive bonding material.
[0025] In the above configuration, the base and the circuit board
may have different coefficients of thermal expansion.
[0026] In this configuration, in which the base and the circuit
board have different coefficients of thermal expansion, a crack is
likely to occur on the conductive bonding material. Still, this
configuration ensures that even if a crack occurs on the conductive
bonding material, the electrical disconnection of the base from the
circuit board is more securely minimized as compared with the
conventional art without the bump. This, as a result, improves the
durability of the conductive bonding material.
[0027] In order to achieve the above-described object, according to
another aspect of the present invention, a package to be mounted on
a circuit board includes the base of the one aspect of the present
invention to hermetically seal an electronic component element, and
a lid.
[0028] With this aspect of the present invention, the package
includes the base of the one aspect of the present invention and
the lid, and the package is to be mounted on the circuit board.
This improves the durability of the conductive bonding material and
minimizes the electrical disconnection of the package from the
circuit board.
[0029] Specifically, with this aspect of the present invention,
forming the bump on the external connection terminal ensures that
even if a crack occurs on the conductive bonding material, the
crack on the conductive bonding material does not develop along the
external connection terminal of the base, but instead develops from
an outer periphery end edge of the external connection terminal
toward an outer periphery end edge of the bump. Thus, a bending
point is ensured where the crack is bent in its course. The bending
point impedes the advancement of a crack itself. This aspect of the
present invention also ensures that even if a crack occurs on the
conductive bonding material, the electrical disconnection of the
base from the circuit board is more securely minimized as compared
with the conventional art without bumps. This, as a result,
improves the durability of the conductive bonding material. This
configuration ensures that the distance of positive-negative
reversal of the direction of strain is extended to equal to or more
than 1.5 times as compared with the conventional art without bumps.
This, as a result, reduces the rate of crack advancement on the
conductive bonding material.
Advantageous Effects of Invention
[0030] The present invention improves the durability of the solder
and minimizes the electrical disconnection of the package from the
circuit board.
BRIEF DESCRIPTION OF DRAWINGS
[0031] FIG. 1 is a schematic diagram illustrating an internal space
of a crystal resonator mounted on a circuit board according to an
embodiment of the present invention.
[0032] FIG. 2 is a schematic rear view of the package according to
this embodiment of the present invention.
[0033] FIG. 3 is an enlarged view of the circuit board and the
crystal resonator shown in FIG. 1, illustrating a state of their
bonding.
[0034] FIG. 4 is a graph illustrating a relationship between the
distance d and the strain in the thickness direction at a bump
thickness of 38 .mu.m.
[0035] FIG. 5 is a graph illustrating a relationship between the
distance d and the strain in the thickness direction at a bump
thickness of 19 .mu.m.
[0036] FIG. 6 is a graph illustrating a relationship between the
distance d and Maximum von Mises Stress at a bump thickness of 38
.mu.m.
[0037] FIG. 7 is a graph illustrating a relationship between the
distance d and Maximum von Mises Stress at a bump thickness of 19
.mu.m.
[0038] FIG. 8 is a schematic rear view of a package according to
yet another embodiment of the present invention.
[0039] FIG. 9 is a schematic rear view of a package according to
yet another embodiment of the present invention.
[0040] FIG. 10 is a schematic rear view of a package according to
yet another embodiment of the present invention.
[0041] FIG. 11 is a schematic rear view of a package according to
yet another embodiment of the present invention.
[0042] FIG. 12 is a schematic rear view of a package according to
yet another embodiment of the present invention.
[0043] FIG. 13 is a schematic rear view of a package according to
yet another embodiment of the present invention.
[0044] FIG. 14 is an enlarged view of a circuit board and a crystal
resonator according to yet another embodiment corresponding to FIG.
3, illustrating a state of their bonding.
DESCRIPTION OF EMBODIMENTS
[0045] Embodiments of the present invention will be described below
by referring to the accompanying drawings. In the following
embodiments, the present invention is applied to a crystal
resonator as a surface-mount piezoelectric resonator device. The
crystal resonators according to the embodiments are applicable to
electronic devices in automotive applications that assume severe,
high and low temperature environments, and in particular,
applicable to principal electronic devices such as ECUs (Engine
Control Units).
[0046] As shown in FIG. 1, a crystal resonator 1 according to this
embodiment includes: a crystal resonator piece 2 (a piezoelectric
resonator piece) made of AT-cut quartz crystal; a base 3 (a part of
a package 11) holding the crystal resonator piece 2 to hermetically
seal the crystal resonator piece 2; and a lid 4 (a part of a
package 11) hermetically sealing the crystal resonator piece 2 held
on the base 3.
[0047] In the crystal resonator 1, the base 3 and the lid 4 define
a package 11. The base 3 and the lid 4 are bonded to one another
with a bonding material 12 to define a hermetically sealed internal
space. In the internal space, the crystal resonator piece 2 is
electrically and mechanically bonded to the base 3 with a
conductive bonding material (not shown). Examples of the conductive
bonding material used include a conductive resin adhesive, a metal
bump, a metallic plating bump, and a brazing filler metal.
[0048] Next, the constituents of the crystal resonator 1 will be
described by referring to FIGS. 1 to 3.
[0049] --Base 3--
[0050] The base 3 is made of a ceramic material (e.g., an alumina
ceramic material). As shown in FIG. 1, the base 3 has a box-shaped
body that includes a bottom portion and a bank portion that extends
upward from the bottom portion along an outer periphery of one
principal surface 31 of the base 3. The base 3 is made of a
rectangular parallelepiped ceramics that is integrally fired on a
single ceramic plate into the form of a depression, with an opening
on top.
[0051] The bank portion of the base 3 has a top face that is a
bonding face for the lid 4. A sealing material of glass (see
reference numeral 12 in FIG. 1) is formed on the top face. The base
3 has a cavity 33 surrounded by the bottom portion and the bank
portion. The crystal resonator piece 2 is disposed in the cavity
33.
[0052] As shown in FIGS. 1 and 2, castellations 35 are formed on
side faces 34 of the base 3. The castellations 35 are disposed at
respective four corners 36 of the other principal surface 32, which
is the reverse face of the base 3. In each of the castellations 35,
a wiring pattern 52 (see below) is formed from the side face 34 to
the other principal surface 32 (at a lower side of each of each
castellation 35) as shown in FIG. 1.
[0053] As shown in FIG. 1, the base 3 includes two electrode pads
51 electrically and mechanically bonded respectively to excitation
electrodes (not shown) of the crystal resonator piece 2. The base 3
further includes: two external connection terminals 6 that are
electrically connected to the circuit board 81; and the wiring
patterns 52 that respectively establish electrical continuity from
the two electrode pads 51 to the two external connection terminals
6. The electrode pads 51, the external connection terminals 6, and
the wiring patterns 52 constitute an electrode 5 of the base 3. The
electrode pad 51 is formed on the one principal surface 31 of the
base 3. The external connection terminal 6 is formed on the other
principal surface 32 of the base 3. The wiring pattern 52 is formed
on the one principal surface 31, on the other principal surface 32,
and on the castellations 35 of the base 3. The electrode pad 51,
the external connection terminal 6, and the wiring pattern 52 each
include a metallized film of tungsten, molybdenum, or the like, and
a layer of Ni plating and a layer of Au plating that are disposed
on the top face of the metallized film.
[0054] As shown in FIG. 2, the two external connection terminals 6
are formed on diagonal positions among the four corners 36 of the
other principal surface 32 of the base 3. The two external
connection terminals 6 are identically shaped in the form of a
rectangular parallelepiped (3.2.times.2.5.times.0.85 mm). The two
external connection terminals 6 have opposing areas 61 that face
each other in the longer side direction and non-opposing areas 62
that do not face each other in the longer side direction. The two
external connection terminals 6 are disposed symmetrically relative
to the center point 38 of the other principal surface 32 of the
base 3, with the non-opposing areas 62 disposed at the respective
corners 36 of the other principal surface 32, and the opposing
areas 61 disposed adjacent to a center position 371 of each of a
pair of shorter sides 37 of the other principal surface 32. As
shown in FIGS. 1 to 3, bumps 7 each including a metallized film of
tungsten, molybdenum, or the like are formed on the external
connection terminals 6. Each bump 7 is shaped similarly to the
external connection terminal 6 with a slightly smaller plane area
than the plane area of the external connection terminal 6. In this
embodiment, each bump 7 is shaped similarly to the external
connection terminal 6 such that the bump 7 has a diagonal line in
plan view that is approximately 0.2 mm shorter than a diagonal line
of the external connection terminal 6. This results in the bump 7
being disposed within the external connection terminal 6 when the
bump 7 is superposed on the external connection terminal 6. A
surface 63 of the external connection terminal 6 and a surface 71
of the bump 7 are flat and oriented in the same direction as the
direction (same surface direction) in which the other principal
surface 32 of the base 3 is oriented.
[0055] --Lid 4--
[0056] As shown in FIG. 1, the lid 4 is made of a ceramic material
(e.g., an alumina ceramic material) and is in the form of a
rectangular parallelepiped single plate that is rectangular in plan
view. On the bottom face of the lid 4, a sealing material such as a
glass sealing material (see reference numeral 12 in FIG. 1) for
bonding the lid 4 to the base 3 is formed. The internal space is
hermetically sealed by a method such as fusion bonding with the lid
4 on the base 3 disposed in a heating furnace of inert gas. Thus,
the package 11 of the crystal resonator 1 is defined by the lid 4
and the base 3.
[0057] --Crystal Resonator Piece 2--
[0058] The crystal resonator piece 2 is a substrate made of a
AT-Cut quartz crystal piece, and has an outer shape in the form of
a rectangular parallelepiped plate as shown in FIG. 1.
[0059] The crystal resonator piece 2 includes: a pair of excitation
electrodes (not shown) for effecting excitation; a pair of terminal
electrodes (not shown) electrically and mechanically bonded to the
electrode pad 51 of the base 3; and leading-out electrodes (not
shown) leading out the pair of excitation electrodes to the pair of
terminal electrodes.
[0060] The pair of excitation electrodes is formed on both
principal surfaces 21 and 22 to face each other. The pair of
excitation electrodes are each made of, for example, a Cr--Au film,
which includes a Cr layer and an Au layer that are stacked in the
order set forth starting on the substrate. The pair of terminal
electrodes are formed on the other principal surface 22, and each
made of, for example, a Cr--Au film, which includes a Cr layer and
an Au layer that are stacked in the order set forth starting on the
substrate, similarly to the excitation electrode. The leading-out
electrodes are formed on both principal surfaces 21 and 22 and on a
side face 23 without facing one another. The leading-out electrodes
are each made of, for example, a Cr-Au film, which includes a Cr
layer and an Au layer that are stacked in the order set forth
starting on the substrate, similarly to the excitation
electrode.
[0061] In the crystal resonator 1 thus configured, the base 3 and
the crystal resonator piece 2 are electrically and mechanically
bonded to one another with a conductive bonding material. This
bonding electrically and mechanically bonds the excitation
electrodes of the crystal resonator piece 2 to the electrode pads
51 of the base 3 via the leading-out electrodes, the terminal
electrodes, and the conductive bonding material, thus mounting the
crystal resonator piece 2 on the base 3. Then the lid 4 is disposed
over the base 3 on which the crystal resonator piece 2 is mounted,
and the sealing material (see reference numeral 12 in FIG. 1)
electrically and mechanically bonds the base 3 to the lid 4. Thus,
the crystal resonator 1 with the crystal resonator piece 2
hermetically sealed therein is fabricated.
[0062] The crystal resonator 1 with the crystal resonator piece 2
hermetically sealed is mounted on the circuit board 81, and then
bonded to the circuit board 81 with a solder 82 (conductive bonding
material) as shown in FIGS. 1 and 3. Thus, the external connection
terminals 6 formed on the base 3 are electrically connected to the
circuit board 81.
[0063] Incidentally, the bonding of the crystal resonator 1 on the
circuit board 81 causes strain on the solder in the thickness
direction.
[0064] In the case of the crystal resonator 1 shown in FIG. 1,
strain-causing stress is at a high level at a corner portion 64 of
the external connection terminal 6. The corner portion 64 is
adjacent to the castellation 35, which is disposed at a corner 36
of the other principal surface 32 of the base 3. The stress
attenuates along a direction from the corner portion 64 toward a
diagonal portion 65 disposed at a diagonal position relative to the
corner portion 64 (the direction in which the stress attenuates on
the principal surface of the base 3 will be hereinafter referred to
as "attenuating direction A of stress").
[0065] In view of this, strain on the crystal resonator 1 according
to this embodiment was calculated over a distance d of 0.01 mm to
0.40 mm. It is assumed that the distance d is a distance (see the
arrow in FIG. 3) between an outer periphery end edge 66 of the
external connection terminal 6 and an outer periphery end edge 72
of the bump 7 along the attenuating direction A of stress. The
results are shown in FIGS. 4 and 5. The thickness of the bump 7 is
set at 38 .mu.m in the calculation shown in FIG. 4, while the
thickness of the bump 7 is set at 19 .mu.m in the calculation shown
in FIG. 5.
[0066] With the thickness of the bump 7 set at 38 .mu.m as shown in
FIG. 4, when the distance d is more than 0.00 mm and equal to or
less than 0.12 mm, the strain is constantly positive, without
reversal. Thus, setting the distance d at equal to or less than
0.12 mm minimizes the advancement of a crack on the solder caused
by the positive-negative reversal of strain. Additionally, when the
distance d is equal to or more than 0.06 mm and equal to or less
than 0.12 mm, the strain is equal to or less than .+-.0.0005, thus
minimizing the strain itself. Thus, setting the distance d at equal
to or more than 0.06 mm and equal to or less than 0.12 mm minimizes
the amount of cracks caused by strain. It is particularly preferred
that the distance d is 0.12 mm, in which case the positive-negative
reversal of strain is eliminated, and a long distance d is
ensured.
[0067] With the thickness of the bump 7 set at 19 .mu.m as shown in
FIG. 5, when the distance d is more than 0.00 mm and equal to or
less than 0.12 mm, the strain is constantly positive, without
reversal. Thus, setting the distance d at equal to or less than
0.12 mm minimizes the advancement of a crack on the solder caused
by the positive-negative reversal of strain. Additionally, when the
distance d is equal to or more than 0.06 mm and equal to or less
than 0.12 mm, the strain is equal to or less than .+-.0.0005, thus
minimizing the strain itself. Thus, setting the distance d at equal
to or more than 0.06 mm and equal to or less than 0.12 mm minimizes
the amount of cracks caused by strain. It is particularly preferred
that the distance d is 0.12 mm, in which case the positive-negative
reversal of strain is eliminated, and a long distance d is
ensured.
[0068] Thus, FIGS. 4 and 5 indicate that no matter how thick the
bump 7 is, the stress in the thickness direction over the distance
d results in similar tendencies. Hence, regardless of the thickness
of the bump 7, the distance d is preferably equal to or less than
0.12 mm, and more preferably, the distance d is equal to or more
than 0.06 mm and equal to or less than 0.12 mm. Regarding the
strain, this embodiment with the bumps 7 ensures that the distance
of positive-negative reversal is extended to equal to or more than
1.5 times as compared with the conventional art without the bumps
7. Hence, the conventional art without the bumps 7 will encounter
significant failures associated with the positive-negative reversal
of strain. Regarding the strain-associated failures, a crack
generally occurs and advances in a positive strain area (in
relation to the distance from the outer periphery end edge 66 of
the external connection terminal 6). The positive strain turns into
negative upon reversal of temperature. Meanwhile, the formerly
negative strain area before the reversal of temperature turns into
positive upon reversal of temperature, so that the crack advances
in the positive turned area. The shorter the distance becomes
between the area where the strain turns into positive and the area
where the strain turns into negative, the more intensely the crack
advances upon reversal of temperature at the time of thermal shock,
thus increasing the rate of crack advancement. Thus, the
positive-negative reversal of strain relates to the failures
encountered in the conventional art.
[0069] Next, Maximum von Mises Stress was calculated at a distance
d of equal to or more than 0.01 mm and equal to or less than 0.45
mm. The results are shown in FIGS. 6 and 7. The thickness of the
bump 7 is set at 38 .mu.m in the calculation shown FIG. 6, while
the thickness of the bump 7 is set at 19 .mu.m in the calculation
shown FIG. 7.
[0070] With the thickness of the bump 7 set at 38 .mu.m as shown in
FIG. 6, when the distance d is equal to or more than 0.06 mm and
equal to or less than 0.45 mm, the Maximum von Mises Stress is kept
at equal to or less than 5.00 E+11 Pa. Thus, the Maximum von Mises
Stress is small in the above range, and the reduction in Maximum
von Mises Stress reduces the amount of cracks. In particular, the
Maximum von Mises Stress is minimized at a distance d of 0.12
mm.
[0071] With the thickness of the bump 7 set at 19 .mu.m as shown in
FIG. 7, when the distance d is equal to or more than 0.06 mm and
equal to or less than 0.45 mm, the Maximum von Mises Stress is kept
at equal to or less than 5.00 E+11 Pa. Thus, the Maximum von Mises
Stress is small in the above range, and the reduction in Maximum
von Mises Stress reduces the amount of cracks. In particular, the
Maximum von Mises Stress is minimized at a distance d of 0.12
mm.
[0072] The crystal resonator 1 according to this embodiment will be
used in electronic devices of automotive applications that assume
severe, high and low temperature environments. In view of this, a
thermal shock test (a temperature change test), which involves
temperature changes, was carried out. The thermal shock test was
carried out to test the electrical connectivity between the crystal
resonator 1 (package 11) and the circuit board 81 in a plurality of
predetermined temperature environments. Specifically, the thermal
shock test was carried out at a high temperature (+125.degree. C.)
and a low temperature (-55.degree. C.). A change of temperature
from the high temperature (+125.degree. C.) to the low temperature
(-55.degree. C.) or from the low temperature to the high
temperature was assumed one cycle. The test was to see up to what
cycles the crystal resonator 1 (package 11) kept electrically
connected to the circuit board 81. The thermal shock test shows
that when the distance d shown in FIGS. 6 and 7 is 0.45 mm, 2000
cycles are accomplished. When the distance d shown in FIGS. 6 and 7
is 0.12 mm, 3000 cycles are accomplished in the thermal shock test
involving temperature changes.
[0073] Thus, FIGS. 6 and 7 indicate that no matter how thick the
bump 7 is, the Maximum von Mises Stress in the thickness direction
over the distance d results in similar tendencies. Hence,
regardless of the thickness of the bump 7, the distance d is
preferably equal to or more than 0.06 mm and equal to or less than
0.45 mm. As described above, the Maximum von Mises Stress is
minimized at a distance d of 0.12 mm.
[0074] FIGS. 4 to 7 indicate that the distance d is particularly
preferably equal to or more than 0.06 mm and equal to or less than
0.12 mm. This eliminates the positive-negative reversal of strain
to thereby minimize the advancement of a crack on the solder 82,
which would otherwise advance due to the positive-negative reversal
of strain. This also keeps the Maximum von Mises Stress at equal to
or less than 5.00 E+11 Pa. The reduction in Maximum von Mises
Stress minimizes the amount of cracks. Additionally, the strain and
the Maximum von Mises Stress are minimized at a distance d of 0.12
mm.
[0075] Next, while the thickness of the bump 7 was varied, the
distance d of strain reversal relative to the thickness of the bump
7 was measured.
[0076] When the thickness of the bump 7 is 38 .mu.m, the distance d
is 0.12 mm. It is assumed that an imaginary line L passes on the
outer periphery end edge 66 of the external connection terminal 6
and the outer periphery end edge 72 of the bump 7. The angle of the
imaginary line L (hereinafter referred to as "bump angle") relative
to a surface of the external connection terminal 6 is 18.degree.
when the thickness of the bump 7 is 38 .mu.m and at a distance d of
0.12 mm. When the thickness of the bump 7 is 19 .mu.m, the distance
d is 0.11 mm, and the bump angle is 10.degree.. When the thickness
of the bump 7 is 0.013 mm, the distance d is 0.0922 mm, and the
bump angle is 8.degree.. Thus, at a distance d of equal to or more
than 0.0922 mm and equal to or less than 0.12 mm, the bump angle is
preferably equal to or more than 8.degree. and equal to or less
than 18.degree.. Keeping the relationship between the distance d
and the bump angle within this range eliminates the
positive-negative reversal of strain. Hence, the range is suitable
for minimizing the advancement of a crack on the solder, which
would otherwise advance due to the positive-negative reversal of
strain.
[0077] With the crystal resonator 1 according to this embodiment,
the external connection terminals 6 to be electrically connected to
the circuit board 81 with the solder 82 are formed on the other
principal surface 32 of the base 3. The bumps 7 smaller than the
external connection terminals 6 are formed on the respective
external connection terminals 6. The distance d along the
attenuating direction A of stress is set at more than 0.00 mm and
equal to or less than 0.45 mm. This improves the durability of the
solder 82 and minimizes the electrical disconnection of the package
11 from the circuit board 81.
[0078] Specifically, with the crystal resonator 1 according to this
embodiment, forming each bump 7 on its corresponding external
connection terminal 6 ensures that even if a crack occurs on the
solder 82, the crack on the solder 82 does not develop along the
external connection terminal 6 of the base 3, but instead develops
from the outer periphery end edge 66 of the external connection
terminal 6 toward the outer periphery end edge 72 of the bump 7
(see the arrow in FIG. 3). Thus, a bending point is ensured where
the crack is bent in its course. The bending point impedes the
advancement of a crack itself. This ensures that even if a crack
occurs on the solder 82, the electrical disconnection of the base 3
from the circuit board 81 is more securely minimized as compared
with the conventional art without the bumps 7. This, as a result,
improves the durability of the solder 82. This configuration also
ensures that the distance of positive-negative reversal of the
direction of strain is extended to equal to or more than 1.5 times
as compared with the conventional art without the bumps 7. This, as
a result, reduces the rate of advancement of a crack on the solder
82 and minimizes cracking on the solder 82, which would otherwise
advance due to the positive-negative reversal of strain.
[0079] Additionally, the package 11 of the crystal resonator 1
according to this embodiment includes the base 3 according to this
embodiment and the lid 4. The package 11 is to be mounted on the
circuit board 81. This ensures the advantageous effects of the base
3 according to this embodiment.
[0080] The external connection terminals 6 are disposed at diagonal
positions among the four corners 36 of the other principal surface
32 of the base 3. The attenuating direction A of stress on each of
the external connection terminals 6 is oriented from the corner
portion 64 of the external connection terminal 6 disposed at a
corner 36 of the other principal surface 32 of the base 3 toward
the diagonal portion 65 disposed at a diagonal position relative to
the corner portion 64. That is, this embodiment, in which the
external connection terminals 6 are disposed diagonally on the
other principal surface 32 of the base 3, ensures that even if a
difference in coefficients of thermal expansion exists between the
base 3 and the circuit board 81, the base 3 rotates about the
center point 38 of the other principal surface 32 to uniformly
distribute the stress.
[0081] Since the base 3 (a ceramic material) and the circuit board
81 (a glass epoxy material) have different coefficients of thermal
expansion, a crack is likely to occur on the solder 82. Still, even
if a crack occurs on the solder 82, the electrical disconnection of
the base 3 from the circuit board 81 is more securely minimized as
compared with the conventional art without the bumps 7. This, as a
result, improves the durability of the solder 82. That is, the
advantageous effects of this embodiment are particularly noticeable
with the base 3 and the circuit board 81 having different
coefficients of thermal expansion.
[0082] While in this embodiment the crystal resonator piece 2 uses
an AT-Cut quartz crystal piece, this should not be construed in a
limiting sense. It is possible to use crystal resonator pieces of
other forms such as a tuning-fork crystal resonator piece.
[0083] While in this embodiment glass is used as the sealing
material of the base 3, this should not be construed in a limiting
sense. If the lid 4 is a metal lid, the sealing material 12 may
include a metallized film of tungsten, molybdenum, or the like with
a Ni plating layer and a Au plating layer covering the top face of
the metallized film. Further, a metal ring may be formed over the
plating layers.
[0084] While in this embodiment a ceramic material is used as the
lid 4, this should not be construed in a limiting sense; it is also
possible to use a glass material or a metal material. The method of
hermetic sealing of the base 3 and the lid 4 is not limited to
fusion bonding. It is also possible to use other methods such as
welding joint and brazing, depending on the materials (of the base
3, the lid 4, the sealing material 12 or the like).
[0085] While in this embodiment each external connection terminal 6
has 1.2.times.1.5 mm dimensions in plan view and each bump 7 has
1.0.times.1.3 mm dimensions in plan view, this should not be
construed in a limiting sense. The external connection terminal 6
and the bump 7 may be set at any dimensions insofar as the distance
d is set in the range of 0.01 mm to 0.45 mm.
[0086] While in this embodiment two external connection terminals 6
are disposed at diagonal positions among the four corners of the
other principal surface 32 of the base 3, this should not be
construed in a limiting sense. As shown in FIG. 8, external
connection terminals 6 may be disposed at all of the four corners
36 of the other principal surface 32 of the base 3. This is a
four-terminal configuration that includes four external connection
terminals 6 formed at the four corners 36, and the attenuating
direction A of stress on each of the external connection terminals
6 is oriented from each corner 36 toward the center (the center
point 38) of the other principal surface 32 of the base 3 (see the
arrows in FIG. 8).
[0087] While in this embodiment two external connection terminals 6
are disposed at diagonal positions among the four corners 36 of the
other principal surface 32 of the base 3, this should not be
construed in a limiting sense. As shown in FIG. 9, a pair of
external connection terminals 6 may be disposed in an opposing
manner along a pair of respective shorter sides 37 on the other
principal surface 32 of the base 3.
[0088] The configuration shown in FIG. 9 is a two-terminal
configuration that includes: two opposing external connection
terminals 6 along the pair of respective shorter sides 37 of the
base 3; and castellations on the respective center positions 371 of
the shorter sides 37. The attenuating direction A of stress on each
of the external connection terminals 6 is oriented from a corner
portion 64 of each external connection terminal 6, which is closest
to a corner 36 of the other principal surface 32 of the base 3,
toward a center position 69 of an opposing side 68 facing a side
67, on which the corner portion 64 of the external connection
terminal 6 is formed (see the arrows in FIG. 9). That is, the
attenuating direction A of stress shown in FIG. 9 is oriented from
the corner portion 64 of the external connection terminal 6, which
is closest to a corner of the other principal surface 32, toward
the side (the opposing side 68) of the external connection terminal
6 closest to the center point 38 of the other principal surface
32.
[0089] With the configuration shown in FIG. 9, symmetrically
disposing the external connection terminals 6 on the other
principal surface 32 of the base 3 minimizes occurrence of stress
on the other principal surface 32 of the base 3. This alleviates
the influence of the difference in coefficients of thermal
expansion. This, as a result, minimizes occurrence of a crack
itself.
[0090] While two external connection terminals 6 are disposed at
diagonal positions among the four corners 36 of the other principal
surface 32 of the base 3, this should not be construed in a
limiting sense. As shown in FIG. 10, a pair of external connection
terminals 6 may be disposed in an opposing manner along a pair of
respective longer sides 39 on the other principal surface 32 of the
base 3.
[0091] The configuration shown in FIG. 10 is a two-terminal
configuration that includes: two opposing external connection
terminals 6 along the pair of respective longer sides 39 of the
base 3; and castellations on the respective center positions 391 of
the longer sides 39. The attenuating direction A of stress on each
of the external connection terminals 6 is oriented from a corner
portion 64 of each external connection terminal 6, which is closest
to a corner 36 of the other principal surface 32 of the base 3,
toward a center position 69 of an opposing side 68 facing a side
67, on which the corner portion 64 of the external connection
terminal 6 is formed (see the arrows in FIG. 10). That is, the
attenuating direction A of stress shown in FIG. 10 is oriented from
the corner portion 64 of the external connection terminal 6, which
is closest to a corner of the other principal surface 32, toward
the side (the opposing side 68) of the external connection terminal
6 closest to the center point 38 of the other principal surface
32.
[0092] The configuration shown in FIG. 10 more effectively
minimizes occurrence of stress in the longer side direction of the
other principal surface 32 of the base 3, where the influence of
the difference in coefficients of thermal expansion is large. This
adds to the advantageous effects of the two-terminal configuration
of opposition across the shorter sides shown in FIG. 9. This leads
to alleviation of the influence of the difference in coefficients
of thermal expansion in the shorter side direction of the other
principal surface 32 of the base 3. This, as a result, more
securely minimizes occurrence of a crack itself.
[0093] In the configurations shown in FIGS. 9 and 10, each external
connection terminal 6 has a dimension that is more than half a side
(the shorter side 37 or the longer side 39) of the base 3. Setting
a dimension of each external connection terminal 6 at equal to or
more than 70% of a side of the base 3 (the shorter side 37 or the
longer side 39) minimizes occurrence of stress in the corresponding
side direction.
[0094] While in this embodiment the surface 63 of the external
connection terminal 6 and the surface 71 of the bump 7 are flat and
oriented in the same direction, this should not be construed as
limiting the shapes of the external connection terminals 6 and the
bumps 7. The bump 7 may be shaped such that the thickness of the
bump 7 increases along the attenuating direction A of stress.
Specifically, the surface 71 of the bump 7 may be tapered relative
to the surface 63 of the external connection terminal 6, or the
surface 71 of the bump 7 may be curved. With this configuration,
the increasing thickness of the bump 7 along the attenuating
direction A of stress causes a crack to develop not along the
surface 63 of the external connection terminal 6 but along the
surface 71 of the bump 7. This ensures that even if a crack occurs
on the solder 82, the electrical disconnection of the base 3 from
the circuit board 81 is minimized as compared with the conventional
art without the bumps 7. This, as a result, improves the durability
of the solder 82.
[0095] While in this embodiment the crystal resonator piece 2 has
an outer shape in the form of a rectangular parallelepiped plate,
this should not be construed in a limiting sense. The areas in
which the excitation electrodes are to be formed and which thus
resonate may be thinner so as to adapt to high frequency
applications.
[0096] While in this embodiment each external connection terminal 6
is in the form of a rectangular parallelepiped and each bump 7 is
in the form of a rectangular parallelepiped on the external
connection terminal 6, this should not be construed in a limiting
sense. For example, as shown in FIG. 11, each external connection
terminal 6 may be formed in an H shape in plan view, and two
rectangular parallelepiped bumps 7 may be formed on each external
connection terminal 6. The two rectangular parallelepiped bumps 7
shown in FIG. 11 are aligned along the X direction (the longer side
direction of the base 3 and the shorter side direction of the
external connection terminal 6) in the same orientation. The two
bumps 7 are disposed on the attenuating direction A of stress. With
the configuration of the external connection terminal 6 and the
bumps 7 shown in FIG. 11, the two bumps 7 are disposed on the
attenuating direction A of stress. This further improves the
durability of the solder 82 as compared with the above embodiment.
Specifically, with the configuration shown in FIG. 11, disposing
the two bumps 7 on the attenuating direction A of stress on the
external connection terminal 6 ensures that even if a crack occurs
on the solder 82, the crack on the solder 82 does not develop along
the external connection terminal 6 of the base 3, but instead
develops from the outer periphery end edge 66 of the external
connection terminal 6 toward the outer periphery end edge 72 of the
bump 7 (see the arrow in FIG. 3). Thus, two bending points are
ensured where the crack is bent in its course. The two bending
points impede the advancement of a crack itself. This ensures that
even if a crack occurs on the solder 82, the electrical
disconnection of the base 3 from the circuit board 81 is more
securely minimized as compared with the above embodiment with the
single bump 7.
[0097] As shown in FIG. 12, which is a different configuration from
the configuration in FIG. 11, each external connection terminal 6
may be formed in a rectangular parallelepiped shape, and two
rectangular parallelepiped bumps 7 may be formed on each external
connection terminal 6. The two rectangular parallelepiped bumps 7
shown in FIG. 12 are aligned along the X direction (the longer side
direction of the base 3 and the shorter side direction of the
external connection terminal 6) in the same orientation. The two
bumps 7 are disposed on the attenuating direction A of stress. The
two bumps 7 are disposed on the attenuating direction A of stress.
The configuration shown in FIG. 12 provides similar advantageous
effects as those of the configuration in FIG. 11.
[0098] As shown in FIG. 13, which is a different configuration from
the configuration in FIG. 11, each external connection terminal 6
may be formed in a rectangular parallelepiped shape, and three
rectangular parallelepiped bumps 7 may be formed on each external
connection terminal 6. The three rectangular parallelepiped bumps 7
shown in FIG. 13 are aligned along the Y direction (the shorter
side direction of the base 3 and the longer side direction of the
external connection terminal 6) in the same orientation. The three
bumps 7 are disposed on the attenuating direction A of stress.
Since the number of the bumps 7 is higher in the configuration in
FIG. 13 than in the configuration in FIG. 11, the durability of the
solder 82 further improves in the configuration in FIG. 13.
[0099] While in this embodiment the bump 7 having a single layer is
formed (stacked) on the external connection terminal 6, this should
not be construed in a limiting sense; the bump 7 may have a
plurality of layers. It is particularly preferred that the
plurality of layers are formed in a stepped manner in a
cross-sectional view as shown in FIG. 14. The bump 7 shown in FIG.
14 includes two layers of bumps 73 and 74 formed on the external
connection terminal 6 in this order. The bumps 73 and 74 have their
outer periphery end edges aligned on the attenuating direction A of
stress (see the imaginary line L in FIG. 14) in this order. Thus,
the bumps 73 and 74 are formed in a stepped manner in a
cross-sectional view as shown in FIG. 14. Disposing the bumps 73
and 74 shown in FIG. 14 on the external connection terminal 6
extends the distance over which a crack develops along the
imaginary line L as compared with the above embodiment, and more
securely impedes the advancement of a crack along the external
connection terminal 6.
[0100] While in the above embodiments the outer periphery end edge
72 of each of the bumps 7, 73, and 74 forms a right angle as shown
in FIGS. 3 and 14, this should not be construed in a limiting
sense. The outer periphery end edge 72 of each of the bumps 7, 73,
and 74 may be tapered or curved.
[0101] The present invention can be embodied and practiced in other
different forms without departing from the spirit, scope, and
essential characteristics of the present invention. Therefore, the
above-described embodiments are considered in all respects as
illustrative and not restrictive. The scope of the invention is
indicated by the appended claims rather than by the foregoing
description. All variations and modifications falling within the
equivalency range of the appended claims are intended to be
embraced therein.
[0102] This application claims priority to Patent Application No.
2010-085232 filed in Japan on Apr. 1, 2010, which is hereby
incorporated by reference in its entirety by claiming the
priority.
INDUSTRIAL APPLICABILITY
[0103] The electronic component package of the present invention is
applicable to surface-mount electronic component packages.
REFERENCE SIGNS LIST
[0104] 1 Crystal resonator
[0105] 11 Package
[0106] 12 Bonding material
[0107] 2 Crystal resonator piece
[0108] 21 One principal surface
[0109] 22 The other principal surface
[0110] 23 Side face
[0111] 3 Base
[0112] 31 One principal surface
[0113] 32 The other principal surface
[0114] 33 Cavity
[0115] 34 Side face
[0116] 35 Castellation
[0117] 36 Corner
[0118] 37 Shorter side
[0119] 371 Center position
[0120] 38 Center point
[0121] 39 Longer side
[0122] 391 Center position
[0123] 4 Lid
[0124] 5 Electrode
[0125] 51 Electrode pad
[0126] 52 Wiring pattern
[0127] 6 External connection terminal
[0128] 61 Opposing area
[0129] 62 Non-opposing area
[0130] 63 Surface
[0131] 64 Corner portion
[0132] 65 Diagonal portion
[0133] 66 Outer periphery end edge
[0134] 67 Side
[0135] 68 Opposing side
[0136] 69 Center position
[0137] 7, 73, 74 Bump
[0138] 71 Surface
[0139] 72 Outer periphery end edge
[0140] 81 Circuit substrate
[0141] 82 Solder
[0142] A Attenuating direction of stress
[0143] d Distance
[0144] L Imaginary line
* * * * *